1. Moon Phases
Describe the changes in the observable shape of the moon over the course of about a month.
Today, we are going to take a closer look at the phases of the moon. By now, you understand that the combination of the Earth’s movement and the moon’s own orbit around the Earth results in the cyclical phases of the moon.
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2. The Earth revolves around the sun and at the same time, the moon is revolving around the Earth.
The position of the moon as it orbits the Earth relative to the sun determines the phase of the moon.
As you see in this picture, the Earth revolves around the sun, while the moon is revolving around the Earth. The position of the moon as it orbits the Earth relative to the sun determines the phase of the moon.
Moon Phases

3. Phases of the Moon
As the moon circles the Earth, the shape of the moon appears to change; this is because different amounts of the illuminated part of the moon are facing us.
The shape varies from a full moon to a new moon.
As the moon orbits or circles the Earth, the shape of the moon appears to change. This is due to the different amounts of the moon being illuminated by the sun. Keep in mind that from here on Earth, we only see the illuminated side of the moon that is facing Earth. The shape of the moon varies from a full moon to a new moon.

4. Phases of the Moon First Quarter Waxing Gibbous Crescent Moon
Full Moon
New Moon
Waning Gibbous
Old Crescent
When we look at the moon up in the sky, it seems like the moon can change its shape. However, this is not true at all. The moon looks different to us at various times during the month because of the Earth’s revolution around the sun and the moon’s orbit around the Earth. The moon, unlike the sun, gives off no light at all. In fact, the moon only reflects light from the sun. Sunlight hits the moon and the Earth differently during the month according to their locations. It takes twenty-eight days for the moon to orbit the Earth. Within this time period, the moon goes through several phases. The lunar phase begins with the new moon and is followed by the crescent moon, first quarter moon, waxing gibbous, full moon, waning gibbous, last quarter, and old crescent moon.
Last Quarter
Phases of the Moon

5. Characteristics of the Moon
The Moon is approximately 384,400 km (239,000 miles) from the Earth.
The Moon is about 1/4 the diameter of the Earth.
The average temperature on the surface of the Moon during the day is 107°C.
The gravity of the Moon is about 1/6 the gravity on the Earth. That means that a person who weighs 180 pounds on Earth would only weigh 30 pounds, if measured on the Moon.
The major feature we can see on the Moon are its craters. These have apparently been caused by the impact from meteors over millions of years.
There are many characteristics unique to the moon. For one, the moon is approximately 384,400 kilometers from the Earth. That is about 239,000 miles. The moon is quite a bit smaller than Earth. In fact, it’s only about one quarter the diameter of Earth. The average temperature of the moon during the day is 107 degrees Fahrenheit. The moon also has less gravity acting on it. The gravity of the moon is only one-sixth the gravity here on Earth. A person weighing 180 pounds on Earth would weigh a mere 30 pounds on the moon. One of the moon’s most distinguishing traits are its craters. If you look at the moon in the night sky, you can see spots and indentations. These are craters and have apparently been caused by the impact of meteors over millions of years.

6. Phases of the Moon New Moon
The NEW MOON is invisible because the lit side is facing away from Earth.
The lunar cycle begins with a new moon. The new moon is invisible to us because the lit side of the moon is facing away from the Earth. The side of the moon we see is not reflecting any sunlight, therefore, we cannot see the moon in the sky.
Phases of the Moon

7. The CRESCENT MOON occurs when a small piece of the moon is visible as the moon revolves around the sun.
The crescent moon is between a half moon and a new moon.
Crescent Moon
The crescent moon occurs when a small piece of the moon is visible. The crescent moon falls right after a new moon, but before a half moon.
Phases of the Moon

8. The moon continues to orbit making a right angle with the sun.
This moon phase is called the FIRST QUARTER MOON or a HALF MOON.
One quarter of an orbit has been completed and only one quarter of the moon’s surface is visible from Earth.
First Quarter Moon
(Half Moon)
The moon continues its orbit to make a right angle with the sun. This causes a first quarter moon, better known to you as a half moon. At this point, it looks like we can see half of the moon shining in the night time sky, but only one quarter of an orbit has been completed and only a quarter of the moon’s surface is visible from Earth.
Phases of the Moon

9. Phases of the Moon Waxing Gibbous Moon
A WAXING GIBBOUS MOON can be seen between the half moon and the full moon.
A waxing gibbous moon can be seen between the half moon and the full moon.
Phases of the Moon

10. A FULL MOON occurs when half of the moon’s surface can be seen from Earth.
This phase can be seen when the Earth is between the sun and the moon.
Full Moon
A full moon occurs when half of the moon’s surface can be seen from Earth. This phase is seen when the Earth is between the sun and the moon. At this phase, the moon shines the brightest because it is a complete reflection of the sun’s rays.
Phases of the Moon

11. A WANING GIBBOUS MOON can be seen between the full moon and the half moon.
The lunar phase then begins to reverse itself sometime around the middle of the month. A waning gibbous moon can be seen between the full moon and the half moon.
Phases of the Moon

12. Phases of the Moon Last Quarter Moon
The moon continues to orbit once again making a right angle with the sun.
This moon phase is called the LAST QUARTER MOON or a HALF MOON.
Three quarters of an orbit has been completed and therefore, three quarters of the moon’s surface is visible from Earth.
Last Quarter Moon
The moon continues to orbit once again, making a right angle with the sun. The moon phase is known as the last quarter moon or a half moon. Three quarters of an orbit has been completed and therefore three quarters of the moon’s surface is visible from Earth.
Phases of the Moon

13. A CRESCENT MOON is visible midway between the half moon and a new moon.
Waning Crescent Moon
After the half moon and before a new moon is the waning crescent moon. This moon is just a sliver of light.
Phases of the Moon

14. Phases of the Moon New Moon One Complete Cycle
The new moon ends and begins the lunar cycle.
Phases of the Moon

15. So, as you can see, the moon follows a routine pattern every 28 days
So, as you can see, the moon follows a routine pattern every 28 days. From a new moon to a first quarter moon, full moon, and last quarter moon, the entire moon is always present, however, we can only see parts illuminated by the sun.
The Phases of the moon